A polymer electrolyte fuel cell (PEFC) extracts energy as electric power from the reaction between hydrogen and oxygen to generate water, which is expected to be useful for future society as a clean power source with no CO2 emission. The use of PEFCs, such as for automobiles, household use fuel cells, and mobile phones, is well known. A component called a separator is used inside the PEFCs. This is mainly a component that forms a flow path for hydrogen and oxygen and allows electricity to flow between cells.
For the material of PEFC separators, two kinds of material, carbon and metal, are generally used. On the basis of the reasoning that carbon is poor in workability and thick, thus increasing size, metallic separators are anticipated in automotive PEFCs. The development thereof has been underway not only at manufacturers but also at research institutions such as universities.
In Non Patent Literature 1, formability, corrosion resistance, contact resistance, and power generation characteristics at a supercooled liquid temperature range are reported for the separator of a metallic glass material.
Patent Literature 1 discloses a manufacturing method in which stainless steel is applied as a base, and in order to make the stainless steel conductive as well, a passive layer is passed through with a deposition, thereby increasing the conductivity between the stainless interior and its surface. A passive layer has high electric resistance, so that contact resistance increases (conductivity deteriorates) when the surface of a material is covered therewith.
Also in Patent Literatures 2 and 3, the material, in which a passive layer is formed on a surface thereof to improve corrosion resistance, is selected, and similarly as described above, special treatment such as plating is performed on the surface in order to improve conductivity.
In Patent Literature 4, the manufacturing apparatus for preparing an amorphous thin plate and the method therefor are disclosed, allowing for a thin plate in a size required for PEFC separators. FIG. 1 shows the structure of an injection gun as a primary device. With this injection gun, a film is formed on a substrate surface while flying powder particles are quenched, finally followed by the release of the film from the substrate so as to obtain an amorphous thin plate.